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66 lines
2.3 KiB
C
66 lines
2.3 KiB
C
19 years ago
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#ifndef RANGECHECK_H
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#define RANGECHECK_H
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#include <stddef.h>
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/* return 0 for range error / overflow, 1 for ok */
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#if defined(__GNUC__) && defined(__OPTIMIZE__)
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#define __static extern
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#else
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#define __static static
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#endif
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/* does ptr point to one of buf[0], buf[1], ... buf[len-1]? */
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__static inline int range_ptrinbuf(const void* buf,size_t len,const void* ptr) {
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register const char* c=(const char*)buf; /* no pointer arithmetic on void* */
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return (c && /* is buf non-NULL? */
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#if (__GNUC__ == 4) && (__GNUC_MINOR__ == 1)
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((size_t)c)+len>(size_t)c && /* gcc 4.1 miscompiles this test */
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#else
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c+len>c && /* catch integer overflows and fail if buffer is 0 bytes long */
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/* because then ptr can't point _in_ the buffer */
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#endif
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(size_t)((const char*)ptr-c)<len); /* this one is a little tricky.
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"ptr-c" checks the offset of ptr in the buffer is inside the buffer size.
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Now, ptr-c can underflow; say it is -1. When we cast it to size_t, it becomes
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a very large number. */
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}
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/* Is this a plausible buffer?
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* Check whether buf is NULL, and whether buf+len overflows.
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* Does NOT check whether buf has a non-zero length! */
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__static inline int range_validbuf(const void* buf,size_t len) {
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#if (__GNUC__ == 4) && (__GNUC_MINOR__ == 1)
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return (buf && (size_t)buf+len>=(size_t)buf); /* gcc 4.1 miscompiles this test */
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#else
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return (buf && (const char*)buf+len>=(const char*)buf);
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#endif
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}
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/* is buf2[0..len2-1] inside buf1[0..len-1]? */
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__static inline int range_bufinbuf(const void* buf1,size_t len1,const void* buf2,size_t len2) {
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return range_validbuf(buf1,len1) &&
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range_validbuf(buf2,len2) &&
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buf1<=buf2 &&
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(ptrdiff_t)buf1+len1>=(ptrdiff_t)buf2+len2;
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}
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/* does an array of "elements" members of size "membersize" starting at
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* "arraystart" lie inside buf1[0..len-1]? */
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int range_arrayinbuf(const void* buf1,size_t len,
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const void* arraystart,size_t elements,size_t membersize);
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/* does an ASCIIZ string starting at "ptr" lie in buf[0..len-1]? */
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int range_strinbuf(const void* buf,size_t len,const void* stringstart);
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/* does an UTF-16 string starting at "ptr" lie in buf[0..len-1]? */
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int range_str2inbuf(const void* buf,size_t len,const void* stringstart);
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/* does an UTF-32 string starting at "ptr" lie in buf[0..len-1]? */
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int range_str4inbuf(const void* buf,size_t len,const void* stringstart);
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#undef __static
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#endif
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